I. Field of the Invention
The present invention is directed to material testing, and more particularly, to a method and device for determining the coefficient of restitution of a rebounding object, such as a ball.
II. Description of the Prior Art
In many sports or games, the ability of a ball to travel or to be directed with precision is very important. It is well known that use reduces the effectiveness and quality of many balls. In many sports, such as golf, tennis, racquetball, or basketball, it is advantageous to determine the condition of the ball in advance in order to determine whether it is acceptable for use.
Rathmell U.S. Pat. No. 3,496,765 discloses a device which drops a ball on a curved surface to deflect the ball upwardly out through an aperture to land on a second curved surface. The ball is then deflected into a sand box for measurement. Rathmell also discloses a prior art testing device in which a ball is dropped from a standard height to a rebound surface A "good" ball follows a predetermined course to rebound through an opening to a second rebound surface and then to rebound through another opening. The trajectory of a "bad" ball prevents it from following the same course.
Nicolaides U.S. Pat. No. 3,777,548; Saari No. 3,509,736; and Mizeljewski No. 3,299,692 disclose impacting a ball with an anvil or the like and measuring the momentum of the ball when it contacts a target.
A third type of tester is disclosed in Gordon U.S. Pat. No. 3,093,995 in which the coefficient of restitution is measured by shooting a golf ball against a moveable target. The moveable target has a mass equal to that of a golf club.
However, the prior devices for quantifying the compression or rebound characteristics of golf balls have been large, complex structures. Such devices are large and expensive. Thus, it would be desirable to provide a device which is suitable for use by individuals or stores to test new or used balls prior to use.